You have a hydraulic self-leveling suspension, which is why no one carries aftermarket struts.

If you wish to retain the system, perhaps you should consider popping in new Nitrogen cells? If you've never changed them, they might very well be shot-however, your symptoms aren't consistent with blown cells, so I wonder....

Are your rear hydro struts (shocks) leaking?

__________________
"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo